Composition and Drug Resistance of Pathogenic Isolates from CSF Culture of Pediatric Patients in Guangzhou / 现代检验医学杂志

Objective To explore the composition and drug resistance characteristics of pathogenic isolates from cerebrospinal fluid (CSF) cultures to facilitate empirical therapy of pediatric patients with meningitis in Guangzhou district.Methods During 2011 Jan 1st to 2015 Dec 31st,cerebrospinal fluids were collected from pediatric patients with suspected meningitis for regular culture,identification and drug susceptibility test of pathogenic isolates according to the national clinical laborato ry standard operation procedure,followed by analysis of their composition and drug resistance characteristics.Results There were 132 pathogenic isolates from CSF cultures,including Gram-positive strains (39.40％,52/132),Gram-negative strains (757.58％,6/132),fungi (3.03 ％,4/132),respectively.The main isolates were Escherichia coli (E.coli) (23.48％,31/132),Streptococcus pneumonia (S.pneumonia) (22.73％,30/132),Staphylococcus aureus (S.aureus) (12.12％,16/132)and Streptococcus agalactiae (S.agalactiae) (9.85％,13/132),respectively.E.coli had no resistance to piperacillin/tazobactam,furantoin,cefepime,amikacin,tobramycin,imipenem,ertapenem and meropenem.3.22 ％ resistance rate to cefotetan,9.38％ to ceftazidime,12.90 ％ to aztreonam,approximately 30 ％ to ampicillin/sulbactam,ofloxacin,ciprofloxacin,ceftriaxone,gentamycin,cefazolin,over 60 ％ to both sulfamethoxazole and ampicillin,31.25 ％ strains were ESBL positive.S.pneumonia had no re sis tance to ertapenem,5.88 ％ resistance rate to telithromycin,14.71％ to chloromycetin,17.76 ％ to ceftriaxone,23.53 ％ to amoxicillin,32.30 ％ to meropenem,35.29 ％ to cefotaxime,over 70 ％ to tetracycline,erythromycin,penicillin,and sulfamethoxazole.S.a ureus had no resistance to rifampicin,tigecycline,quinuprin/dupletin,linezolid and vancomycin,6.25％ resistance to ciprofloxacin,6.25％ to gentamicin,12.50％ to sulfamethoxazole,18.75％ resistance to clindamycin,31.25 ％ to tetracycline,62.50 ％ to erythromycin,over 90 ％ to cephalosporins and nearly 100 ％ to penicillin,the rate of MRSA strain was 56.25 ％.S.agalactiae had no resistance to penicillin,23.08 ％ resistance rate to ofloxacin,7.69 ％ to ciprofloxacin,over 60％ to tetracycline,erythromycin and clindamycin.Conclusion The main pathogenic isolates from CSF cultures were E.coli,S.pneumonia,S.aureus,S.agalactiae,different species of isolates have different drug resistance characteristics.This will provide instructions for the prevention,pathogenic diagnosis and treatment of meningitis in pediatric patients.

Cloning and sequence analysis of UreB of Helicobacter pylori isolated from children / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To clone UreB gene of Helicobacter pylori (H. pylori) isolated from children to pGEX-4T-1 expression plasmid, and do sequence analysis.</p><p><b>METHODS</b>A pair of specific primer was designed according to H. pylori UreB gene in the GenBank. Using H. pylori strains isolated from children as a template, a UreB gene was obtained by PCR. After EcoR I and Not I digestion, the PCR production was linked with pGEX-4T-1 which was digested with the same enzymes. The recombinant plasmid was transformed into E.coli BL21 and identified by double enzyme digestion and sequence analysis. The sequence results were compared with the gene sequence in the GenBank.</p><p><b>RESULTS</b>A UreB gene was successfully amplified from children's H. pylori strain GZCH1. It was 1710 bp in size. The objective band was identified by double enzyme digestion. DNA sequence showed that UreB was in the correct open reading frame. The sequence comparison analysis showed that DNA and amino acid sequence identities of UreB gene with other strains were 98%. The sequence of UreB of H. pylori strain GZCH1 was submitted to GenBank (accession number:FJ455126).</p><p><b>CONCLUSIONS</b>UreB of H. pylori strain GZCH1 is successfully cloned to pGEX-4T-1, which provides a basis for research of oral H. pylori vaccine.</p>

Investigation of campylobacter jejuni infection in children with diarrhea in Guangzhou / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the incidence of campylobacter jejuni (CJ) infection and the drug resistance of CJ in children with diarrhea in Guangzhou.</p><p><b>METHODS</b>The fecal samples of 3,351 children with diarrhea between July 2005 and June 2008 were collected for CJ culture. The species of CJ strains were identified by Lior methods. The drug susceptibility tests were performed by the Kirby-Bauer method.</p><p><b>RESULTS</b>Two hundred and sixty-seven CJ strains (8.0%) were isolated from 3,351 samples. The children at age of 1 month to 1 year were susceptible to CJ, accounting for 91.0%. A higher incidence of CJ infection (76.8%) was found in summer and autumn. The CJ strains were susceptible to imipenem, amikacin, cefoperazone/sulbactam, chloramphenicol, macrolides and lincomycins. Parts of CJ strains (20%-40%) were resistant to ampicillin, quinolones and ambramycin. All CJ strains were resistant to sulfamethoxazole/trimethoprim and cefditoren. Two hundred and one strains (75.3%) were CJ biotype I.</p><p><b>CONCLUSIONS</b>CJ is an important pathogen of diarrhea in children from Guangzhou. CJ is resistant to some antibiotics used often in clinical practice, and so it is thus important to use antibiotics based on the results of drug susceptibility tests in children with CJ infection.</p>

Antimicrobial resistance and penicillin resistance-associated genes of Streptococcus pneumoniae isolated from children with respiratory tract infection / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the antimicrobial resistance and penicillin resistance-associated genes (TEM and pbp2B) of Streptococcus pneumoniae (S. pneumoniae) isolated from sputum specimens of Guangzhou children with respiratory tract infection.</p><p><b>METHODS</b>E-test and Kirby-Bauer methods were applied to detect the antibiotic susceptibility of 44 strains of S. pneumoniae. PCR was used to detect resistance genes pbp2B and TEM, followed by DNA sequence analysis of pbp2B gene. The sequence results were compared to those of penicillin-susceptible S. pneumoniae R6.</p><p><b>RESULTS</b>Of the 44 isolates of S. pneumoniae, only 5 (11.4%) were susceptible to penicillin. All strains were resistant to erythromycin but susceptible to ofloxacin and vancomycin. The resistance rate of the isolates to clindamycin and trimoxazole was more than 90%. The S. pneumoniae isolates showed a high susceptibility to amoxicillin, imipenem and ceftriaxone, with a resistance rate of 0, 2.6% and 3.9%, respectively. The sequence analysis showed that more than 99% nucleotide sequence of pbp2B gene of five penicillin-susceptible isolates was the same as penicillin-susceptible S. pneumoniae R6, without any amino acid replacement. Site mutation was found in the remaining 39 penicillin-nonsusceptible isolates with a nucleotide mutation rate ranging from 13.2% to 23.1% and amino acid replacement rate from 6.5% to 10.9%. The 39 penicillin-nonsusceptible isolates were classified into 4 types according to the mutation site between Ser391 and Thr492 of pbp2B: type I (n=30), type II (n=7), type III (n=1) and type IV (n=1). No TEM gene was detected in all the 44 S. pneumoniae isolates.</p><p><b>CONCLUSIONS</b>The S.pneumoniae isolates from Guangzhou children with respiratory tract infection are resistant to penicillin and erythromycin. Amoxicillin and the third generation cephalosporin may be recommended for treating S. pneumoniae infection. The mutation of pbp2B gene plays an important role in the development of S. pneumoniae resistance to penicillin.</p>